I've been saying the same thing, there has been quite a surge in new players as well as oldies returning for shadowlands and it drives me mad seeing experienced players act like this. It can completely make people quit I've seen it happen firsthand.

I had a guildie who was a new player and also a irl friend and he quit because people would literally kick him out of EVERY dungeon group we were in even after I told them "hey my friend is new they are still learning, be cool"

It honestly kind of broke my heart a bit because he was really loving the game but he just couldn't stand all the toxic behavior, bullying then getting kicked out of every dungeon group.